Functions of operating systems

How do we use the sumif formula (when dealing with different formats) ?

Jason works as an accountant in a department store. he needs to keep a daily record of all the invoices issued by the store. which file naming convention would him the most? a)give the file a unique name b)name the file in yymmdd format c)use descriptive name while naming the files d)use capital letters while naming the file

Spoons are designed to be used for: spring hammering. applying body filler. identifying high and low spots. sanding highly formed areas.